PROBLEM: To study effects of interleukin-11 (IL-11) on blastocyst development and decidualization.
METHOD OF STUDY: Rats, injected with buffer (C) or IL-11 [1 mg/kg/day=high dose (HD), 60 μg/kg/week=low dose (LD)-1, 30 μg/kg twice a week=low dose (LD)-2] were made pregnant or pseudopregnant to obtain blastocysts or deciduomata.
RESULTS: As compared with C, more LD-2 blastocysts hatched in culture, while hatching and attachment of HD blastocysts was decreased. Blastocysts from untreated rats in IL-11 supplemented medium (4 ng/mL) demonstrated increased hatching and attachment. The weight of the decidualized uterus in HD and LD-2 pseudopregnant rats was reduced as compared with C and LD-1. On deciduomata sections from IL-11 treated rats, the area inside the uterine muscle layer was reduced, and mitotic over pycnotic indices were increased in the anti-mesometrial area and decreased in the mesometrial area.
CONCLUSIONS: Low doses of IL-11 improve hatching and attachment of blastocysts, but both high and low doses impair decidualization.